Thompson was born in March 13, 1991 in Toronto, Ontario, Canada. He used to play basketball from an early age. Thompson represents his country Canada in international level. Basketball analytics service Draftexpress describes Thompson as a player who has promising ability to move without the ball.
Thompson spent his sophomore and half of his junior year at St Benedict's Preparatory School. He played brilliantly during his time at St Benedict's. After having a conflict with the St Benedict's coach Dan Hurley, Thompson decided to leave St Benedict's after playing 21 games for them. Then Thompson joined Findlay in Nevada and there also he played brilliantly under coach Michael Peck. He helped to lead Findlay to their first and second National Championship. Thompson played for Texas Longhorns in 2010-2011. He averaged 13.1 points and 7.8 rebounds per game and won the team's most valuable player in that season as he helped his team to reach the NCAA Tournament Round of 32. On April of 2011, he was declared for NBA draft. He was drafted fourth overall by Cleveland Cavaliers in the 2011 NBA draft and signed professional contract with them. Thompson made his professional debut for Cleveland Cavaliers against his hometown Toronto Raptors on December 26, 2011. He scored 12 points and pulled in 5 rebounds in his debut match as he came off the bench. In his first season, he played 60 games (starting 25), averaging 8.2 points per game and pulling in 6.4 rebounds per game. In 2012-2013 season, Thompson started all 82 games for Cleveland Cavaliers as he averaged 11.7 points, 9.4 rebounds (highest in his career) and 0.9 blocks playing 31.3 minutes per game. Thompson switched his shooting hand from left to right in 2013-2014 season. During that season, he started all 82 games for Cleveland Cavaliers, as he averaged 11.7 points, 9.2 rebounds and 0.4 blocks playing 31.6 minutes per game. Thompson came off the bench for the most of 2014-2015 season playing all 82 games (starting 15), averaging 8.5 points and 8 rebounds per game. His team made the playoffs in that season. He started most of the games of playoffs and the Cavaliers reached the 2015 NBA finals where they lost to Golden State Warriors. Thompson represents Canada in international level. He has participated in FIBA Americas U18 Championship in 2008 and 2009 FIBA Under-19 World Championship. Thompson finished his college degree from University of Texas.
Thompson's parents are from Jamaica. He has 3 brothers and all of them are basketball players. There are rumors that, he has an affair with model Jordan Craig. Thompson and his girlfriend Criag do not share any children as of 2015 and they are not married yet.
Thompson has a good physique as he is 6ft 9 inches tall and weighs 108 kg. He has won 2011 Big 12 Freshman of the Year, bronze medal in FIBA Americas U18 Championship 2008 and was included in 2011 All-Big 12 Second Team, 2011 Big 12 All-Defensive Team and NBA’s All-Rookie Second Team for the 2011-12 season. Thompson's net worth is about $18 million and his salary is about $5.3 million per year.